Development of the Internet technology is contributing to the popularization of precision electronic equipment such as a computer. Into such personal computer, there are mounted a storage device such as a hard disk drive and a magnetooptic device, and a mechanical component such as a cooling fan. On the other hand, along with popularization of a personal computer, demands for maintaining data safely have become strong.
For example, for a storage device, capacity increase of a storage capacity is required, and also required is to store various kinds of data such as image data and analytical data safely and certainly.
Accordingly, in Japanese Patent Application Laid-Open No. 2002-272172, for example, a technology for detecting abnormality of a hard disk by monitoring an electric current supplied from a motor driver circuit to a fluid-dynamic-bearing spindle motor is being proposed.